The present invention relates to an optical position detecting device for optically detecting a position indicated by an indicator within a predetermined region on a computer""s display screen or the like.
With the spread of computer systems, mainly personal computers, there has been used a device for inputting new information or giving various instructions to a computer system by pointing at a position on a display screen of a display apparatus on which information is displayed by the computer system, by an indicator such as a person""s finger or a specific tool. In order to perform an input operation with respect to the information displayed on the display screen of the display apparatus of a personal computer or the like by a touching method, it is necessary to detect a touched position (indicated position) on the display screen with high accuracy.
As one example of a device for detecting such an indicated position on the display screen that functions as a coordinate surface, Japanese Patent Application Publication No. 62-32491/1987 discloses an optical position detecting device. This device comprises: an indicating member for pointing at a display screen; at least two optical scanners for emitting scanning light on the display screen; a reflecting member for reflecting the scanning light; and means for detecting a time at which the scanning light struck the indicating member, and detects the position of the indicating member on the display screen, based on the relation between the optical scanning start time or end time of the optical scanners and the time at which the scanning light struck the indicating member.
Besides, another optical position detecting device is disclosed in Japanese Patent Application Laid-Open No. 57-211637/1982. This device angularly scans converged light such as a laser beam from the outside of the display screen, calculates angles at which a special pen having reflecting means exists from two timings of reflected light from the special pen respectively, and detects the coordinates of the position from the calculated angles using the triangulation principle.
Further, still another optical position detecting device is proposed in Japanese Patent Application Laid-Open No. 62-5428/1987. In this device, a light retro-reflector is positioned on a frame on both sides of the display screen, return light of an angularly scanned laser beam from the light retro-reflector is detected, an angle of a position where a finger or a pen exists is calculated from a timing that the light beam is cut off by the finger or the pen, and the coordinates of the position is detected from the calculated angle using the triangulation principle.
None of the conventional optical position detecting devices as described above has a mounting structure because these devices are incorporated by reforming the front part of the body of an existing display apparatus, and thus there is a problem that they are not easily handled. In addition, since the conventional optical position detecting devices have a configuration which is adoptable only to a display screen of a predetermined size, there is such a time-consuming problem that it is necessary to fabricate a special optical position detecting device according to each of various sizes of display screens.
The present invention has been achieved in view of such circumstances, and an object of the present invention is to provide an optical position detecting device that can be easily mounted on an existing display apparatus.
Another object of the present invention is to provide an optical position detecting device that is adoptable to various sizes of display screens, eliminates the necessity of fabricating a special detecting device according to each size of display screen, and yields good productivity.
An optical position detecting device of the first aspect comprises: a light retro-reflector; at least two optical transceiver units, each including an optical scanning unit for angularly scanning light in a plane and a light receiving unit for receiving reflected light of the scanning light from the light retro-reflector; and an external mounting member for mounting the light retro-reflector and the optical transceiver units on an apparatus including a predetermined region to be detected (for example, a display apparatus including a display screen).
Since the optical position detecting device of the first aspect is externally mountable on a display apparatus or the like by the external mounting member, it can be easily mounted on an existing display apparatus.
An optical position detecting device of the second aspect is based on the first aspect, wherein the external mounting member includes a changing mechanism that can adjust the positions of the light retro-reflector and the optical transceiver units.
The optical position detecting device of the second aspect can change the positions of the light retro-reflector and the optical transceiver units according to the size of a display screen, for example, and can correspond to various sizes of display screens.
An optical position detecting device of the third aspect is based on the second aspect, wherein the changing mechanism comprises a slide part that moves in one direction and a guide part that guides the movement of the slide part.
The optical position detecting device of the third aspect can correspond to any size of display screen by moving/adjusting the slide part along the guide part.
An optical position detecting device of the fourth aspect is based on the third aspect, wherein an overlapped portion of the light retro-reflector is present at the joint between the slide part and the guide part.
In the optical position detecting device of the fourth aspect, since such an overlapped portion of the light retro-reflector is provided, the light retro-reflector does not form an uneven portion at the joint between the slide part and the guide part, and therefore detection characteristics do not deteriorate.
An optical position detecting device of the fifth aspect is based on the first through fourth aspects, wherein the external mounting member includes an elastic body on a face to be attached to the display apparatus or the like.
Even when the display screen has a tapered shape, the optical position detecting device of the fifth aspect exhibits high adhesion with the display screen, thereby certainly fixing the display screen.
An optical position detecting device of the sixth aspect comprises a light retro-reflector mounted on a portion with a difference in level on the periphery of the display screen.
In the optical position detecting device of the sixth aspect, a position changing mechanism with respect to the light retro-reflector is unnecessary, thereby reducing the size of the structure. Moreover, since the scanning light is not apart from the display screen, the operability is improved.